Fluid motor

ABSTRACT

A hydraulic motor includes a primary drive piston for driving a motor shaft which oscillated within a main housing chamber. A secondary linearly reciprocating drive piston is disposed within an auxiliary housing chamber for driving a secondary drive shaft. A shuttle-type reversal valve and conduits route pressurized fluid alternately to and from opposite sides of the primary piston to cause oscillation during running of the motor and to park it in a position beyond its running range. The controller valve and conduits also route pressurized fluid to and from opposite sides of the secondary piston through sequence valving to effect reciprocation thereof. The sequence valving is actuated when the primary piston is oscillated and preferably only at the time when the primary piston is moving to or from its park position. Thus the primary drive shaft can run continuously to operate a pair of windshield wipers, for example, while the secondary drive shaft can run only when the wipers move to and from a concealed parking position beyond the normal running range to operate a cowl panel, for example, which conceals the wipers in a parked position and opens to permit operation of the wipers.

United States Patent DAlba Feb. 29,1972

[72] Inventor:

[s21 u.s.c1 ..91/1s9,91/31o,91/339 1511 1111.01. ..F01l33/00,F0ll25/06,F0lc9/00 5s FieldofSearch ..9l/3l0,36,337,338,339, 91/189 [56] References Cited UNITED STATES PATENTS 3,100,423 8/1963 DAlba ..91/31o 3,153,98510/1964 Rileyetal ....91/31o 3,296,938 1/1967 l-layman ...91/310 3,379,099 4/l968 Missiouy ..9l/36 Primary ExaminerPaul E. Maslousky At!omeyE. Herbert Liss [5 7] ABSTRACT A hydraulic motor includes a primary drive piston for driving a motor shaft which oscillated within a main housing chamber. A secondary linearly reciprocating drive piston is disposed within an auxiliary housing chamber for driving a secondary drive shaft. A shuttle-type reversal valve and conduits route pressurized fluid alternately to and from opposite sides of the primary piston to cause oscillation during running of the motor and to park it in a position beyond its running range.

The controller valve and conduits also route pressurized fluid to and from opposite sides of the secondary piston through sequence valving to effect reciprocation thereof. The sequence valving is actuated when the primary piston is oscillated and preferably only at the time when the primary piston is moving to or from its park position. Thus the primary drive shaft can run continuously to operate a pair of windshield wipers, for example, while the secondary drive shaft can run only when the wipers move to and from a concealed parking position beyond the normal running range to operate a cowl panel, for example, which conceals the wipers in a parked position and opens to permit operation of the wipers.

10 Claims, 10 Drawing Figures PATENTEDFEB29 I972 3,645,168

sum 1 or 6 INVENTOR. ANTHONY P. DALBA A TTORNEX PATENTEUFEB 29 I972 SHEET 2 BF 6 I INVENTOR. ANTI-ION) R. D 14L5A ATTORNEK PATENTEDFEB29 m2 3.645.168

SHEET 5 OF 6 II/ as I Fig 7 as 10 I INVENTOR. ANTHONY R. D'ALBA A TTORNEY PAIENTEDFEB 29 I972 3.645.168

SHEET 8 OF 6 15 170 F1910 BY ATTOIZNEY,

FLUID MOTOR BACKGROUND OF THE INVENTION The present invention relates to an improved pressurized fluid motor and more particularly to an improved pressurized fluid motor with a multiple output.

Hydraulic and other fluid pressure motors are known which can produce an oscillating rotary output or a linearly reciprocating output at the drive shaft and which include a running range and a parking position beyond the running range.

A motor of the oscillating type is described in U.S. Pat. No. 3,100,423 by Anthony R. DAlba, issued Aug. 13, 1963, and assigned to Trico Products Corporation, Buffalo, New York. Prior art fluid motors are inherently capable of performing only a single operation; auxiliary linkage or gearing is required to convert from linear reciprocating motion to oscillatory rotary motion or vice versa and sequential operation of two or more outputs requires even more auxiliary equipment.

The improved fluid motor of the present invention is a selfcontained unit which includes both a linearly reciprocating output shaft and an oscillatory rotating output shaft. The dual operation is accomplished by utilization of a secondary piston, and some additional conduits and valving within the motor. Only the addition of a relatively small auxiliary cylinder for the secondary piston is required. A desired sequence of operation of the respective outputs can be achieved without employing gearing and linkage. The overall space required for the motor is substantially the same as the space required for an equivalent motor capable of performing only a single operation; the cost of the additional function is negligible, particularly, relative to the cost of linkage and gearing. Since the operation is sequential and since no additional linkage or gearing is needed no additional power is required.

The novel motor of this invention includes a vane-type primary piston which has secured thereto a primary oscillatory drive shaft and a linearly reciprocating secondary piston which has secured thereto a secondary drive shaft. A control valve assembly is provided which functions to start, park and control the speed of the motor as well as a pressure-regulating and bypass valve. A shuttle-type reversal valve ultimately routes pressurized fluid through conduits to opposite sides of the primary piston while effecting discharge of fluid from the other side thereof to cause oscillation of the primary piston and drive shaft. A pilot valve is actuated by the primary drive shaft and routes fluid to and from the reversal valve to cause shifting thereof which in turn causes reversal of the primary piston. A sequence valve actuated by engagement with the primary piston at an end of a stroke controls the routing of pressure to and from the secondary piston to control reciprocation thereof in a sequence determined by the position of the primary piston.

The sequence valve is located so as to be actuated only when the primary piston moves to and from its parked position beyond the running range. Pressurized fluid to and from the opposite side of the secondary piston is routed through conduits in circuit with the sequence valve. Thus the secondary piston is moved in one direction just prior to movement of the primary piston to parked position and in the opposite direction just subsequent to the return of the primary piston to parked position. During oscillation of the primary piston in the running range the secondary piston does not move. In the particular embodiment illustrated the primary drive shaft drives a pair of windshield wipers which are concealed below the cowl of a vehicle when the wipers are parked. A cover panel for concealing the wipers is driven by the secondary drive shaft.

Although the invention is illustrated embodied in a concealed windshield wiper system it will of course be understood that in accordance with the broader aspects of the invention, the motor may be utilized for other and different applications where dual sequential output is required.

The principal object of the invention is to provide an improved, self-contained, fluid motor capable of providing a plurality of distinct outputs.

Another object of the invention is to provide an improved, self-contained, fluid motor capable of providing a plurality of distinct outputs in a desired sequence.

Other objects and advantages of the invention will be apparent from the following detailed description taken in con nection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary perspective view of an automotive vehicle incorporating the improved wiper motor of the present invention;

FIG. 2 is, an exploded perspective view of the coverplate of the improved wiper motor of the present invention;

FIG. 3 is an exploded perspective view of the improved motor of the present invention;

FIG. 4 is a schematic view of the wiper motor of the present invention showing the position which it assumes when the piston is moving in a counterclockwise direction;

FIG. 5 is a schematic view of the wiper motor of the present invention, the wiper motor being in parked position;

FIG. 6 is a schematic view of the wiper motor of the present invention showing the position which it assumes immediately after it has been started and when the piston is moving in a clockwise direction;

FIG. 7 is a schematic view of a modified form of the present invention similar to FIG. 4;

FIG. 8 is a schematic view of the present invention in the form shown in FIG. 7, the wiper motor being in parked position;

FIG. 9 is a vertical section taken on line IX-IX of FIG. 2; and

FIG. 10 is a lateral section taken on line X--X of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. I an automotive vehicle 10 is shown having a windshield 12 mounted thereon in a conventional manner. Suitably mounted on the firewall of the vehicle by use of lugs 12 is the hydraulic motor 14 of the present invention. A con trol, not shown, mounted on the vehicle dashboard is coupled to lever 16 of the wiper motor through a Bowden cable 18. The source of hydraulic fluid for motor 14 is hydraulic pump 20 which is driven directly from vehicle engine 22, pump 20 receiving its supply of hydraulic fluid from reservoir 24 through conduit 23. The high-pressure hydraulic fluid may be conducted to a hydraulically operated vehicle accessory 28, as for example a power steering control valve, through conduit 30. The exhaust from the accessory 28 may be routed to the motor inlet 32 in control housing 34 through conduit 26. The hydraulic fluid then passes through conduit 36 back to the reservoir 24 whether the wiper motor is in operation or parked. Whenever the wiper motor 14 is in operation, wipers 15 which are mounted on arms 17 and 17 will be oscillated across the windshield. The wiper arms 17 and 17' are driven from the output of the wiper motor 14 through a suitable linkage consisting oflinks l3, 19, 21 and 21'.

The vehicle 10 includes a cowl cover panel 38 hingedly connected to the firewall at 40 and 40', the hinges 40 and 40' being connected by a torsion bar 42. The motor 14 includes a secondary output shaft which drives a lever and latch mechanism 44 secured to the torsion bar 42 for rotation therewith. The wiper arms 17 and 17 and blades 15 when parked and out of use are stowed beneath the cover panel 38 at the lower edge of the windshield 12. The cover panel 38 is driven by the motor 14 through latch and lever assembly 44 to open position prior to running of the wipers and to closed position after the wipers are parked. An example of the lever and latch assembly is described in detail in application Ser. No. 12,627 by D. Papadatos, et al., filed concurrently herewith and assigned to the assignee of the present invention.

The wiper motor 14 of the present invention includes motor housing 46, a cover plate 50 and a porting plate 58. Bolts 54 secure the housing 46 and cover plate 50 in assembled relationship with porting plate 58 therebetween. Seated in grooves 52 and 52' of the housing 46 and cover plate 50, respectively, on each side of the porting plate 58 are a pair of O-ring gaskets 56. A drive shaft 60 has its rear endjournaled in and extending through a suitable bearing 62 mounted in the rear wall of the motor housing. Mounted on the exposed portion of the rear end of shaft 60 is a universal drive 66 which is adapted to engage link 13 for driving the latter. Secured to the intermediate portion of shaft 60 is a vane-type primary drive piston 68 which engages the three walls of the chamber 69 in which the piston is adapted to oscillate. The shaft 60 extends through an opening 71 in porting plate 58 aligned with bearing 62. A substantially cylindrical pilot valve is journaled in bearing recess 64 and includes a tooth 72 extending radially inward from its inner periphery. The outer end 74 of the shaft 60 has a flattened portion 75 and is journaled in the pilot valve 70. It is disposed so that the flat surface 75 of the shaft 60 can engage tooth 62 near the end of a stroke in either direction to thereby cause reversal of the pilot valve 70. Pilot valve 70 is seated on a spring washer 73. The bearing recess 64 includes an axial slot 76 which receives a ball 78. The pilot valve 70 includes a circumferential notch 80 which receives the ball 78, the ball 78 thereby serving as a stop to limit the oscillatory motion of the pilot valve 70. The cover plate 50 has a hollow cylindrical secondary motor chamber 82 formed on the outer wall thereof. A drive shaft 86 extends through opening 84 in the inner end wall of cylinder 82 formed by the cover plate 50. A cylindrical piston 88 is secured to the outer end of shaft 86 and is disposed for reciprocation within cylinder 82. The outer end of the cylinder is closed by a closure plate 90, washers 90 and 90" and a circumferential retaining ring 92. The shaft 86 extends through aligned apertures 84, 84 and 84" in cover plate 50, porting plate 58 and motor housing 46, respectively. An attaching clevis 94 may be secured to the free exposed end of the drive shaft 86. Formed on the outer side of the cover plate 50 is control valve housing 34 for receiving a control valve assembly 97. Formed on the outer side of the motor housing 46 is a reversal valve housing 98 for receiving a shuttle-type reversal valve 100, slidably therein. Inlet port 32 is formed in the control valve housing 34 and outlet port 102, communicating with exhaust chamber 103, is formed in the housing 46 adjacent the reversal valve housing 98. Exhaust chamber 103 is formed on the inner face ofmotor housing 46.

The reversal valve housing 98 comprises a biasing section having cylindrical bore closed at its ends by cover plates 104 and retaining rings 106. Rubber plugs 108 are located at the ends of the reversal valve chamber 98 to cushion the reversal valves at the end of its travel. The control valve housing 96 includes a cylindrical bore closed at one end by a closure cap 110, a washer 110 and a retaining ring 110" in which control valve assembly 97 moves as described in greater detail hereinafter. Lever 16 is mounted on lug 113 of control housing 96 by rivet 114. The end of the control housing adjacent the lever 16 has a plug 115 secured therein in any suitable manner as by a press fit. A stem 116 is mounted for reciprocatory movement in plug 115. It is spring biased outwardly as by spring 117 and the other end of the stem 116 engages the lever 16.

A pressure-regulating piston 118 is located in a chamber 120 of control housing 96 which is slightly larger than the bore 122 for receiving the control valve assembly (see FIGS. 4, 5 and 6). A shoulder 124 limits the movement of the pressure regulating piston 118 to the right and the face of the closure cap 110 limits its movement to the left. Control valve assembly 97 includes a control valve 97' and a bypass and regulating valve 97". Control valve 97' is hollow, open at one end, and has radial apertures 126 through the wall centrally thereof and a small opening 128 at the closed end thereof. The open end of control valve 97' is formed into a conical seat. The pressureregulating valve 97" is of a substantially hollow cylindrical form and includes a valve 130 for engaging the conical seat on the control valve 97, a stem 132 and a piston 134 adapted to ride in the bore of control valve 97. A protruberance 136 is located proximate valve 130 for mounting one end of a spring 138, the other end thereof being positioned within recesses 140 of pressure-regulating piston 118.

When the Bowden cable 18 moves in response to manipulation of the dashboard control to cause lever 16 to move from its position shown in FIG. 5 to its position shown in FIG. 6, stem 116 will move to the left to move control valve assembly 97 from its position shown in FIG. 5 to its position shown in FIG. 6. It is by manipulation of the lever 16 that the wiper motor is turned on and off, that its speed is adjusted and that the piston 88 is caused to move sequentially with respect to the main piston 68.

When the wiper motor 14 is in the parked position shown in FIG. 5 hydraulic fluid passes from the pump 20 to the accessory 28 through conduit 30 and then into the inlet 32 of control housing 96 through conduit 26. Thereafter the hydraulic fluid passes into the bore 122 of control housing 96 between lands 142 and 144 of control valve 97 through openings 126, through bore 146 of the control valve 97' past valve 130 which is sufficiently moved away from its seat so as to create a very slight resistance to flow, thence into the portion of control housing between valve 130 and pressure-regulating piston 118, then through passage 148 of cover plate 50 through opening 148' in porting plate 58 to exhaust chamber 103 of housing 46 and thence through outlet port 102. Furthermore the hydraulic fluid passes into the control housing 96 between lands 142 and 144 through port 149 into pressure chamber 150 in the cover plate 50 and thence through opening 150 in the porting plate which is in communication with duct 150" in the motor housing 46. Thereafter the hydraulic fluid passes between lands 152 and 154 of the reversal valve 100 and then into duct 158 leading to the motor chamber to the left of piston 68 as viewed in FIGS. 4, 5 and 6. From the duct I58 highpressure fluid will pass to the secondary motor chamber 82 on the upper side of piston 88 as viewed in FIGS. 4, 5 and 6 through conduit 160, aperture 162 in porting plate 58 and aperture 164 in cover plate 50.

The portion of chamber 69 to the right of piston 68 will pass to the exhaust port 102 through duct 156 and the portion of reversal valve housing 98 between lands 152 and 196 to exhaust chamber 103. The portion of auxiliary motor chamber 82 below piston 88 as viewed in FIGS. 4, 5 and 6 will communicate with the exhaust port 102 through port 197, conduit 198 on the external surface of the cover plate 50, conduit 200, opening 200' in the porting plate 58, port 200 in sequence valve chamber 202 which is formed in motor housing 46 adjacent the right or parking side of chamber 69, through sequence valve 210 and port 204, conduit 206, duct I56, reversal valve housing 98 between lands 152 and 196 of reversal valve 100, thence to exhaust chamber 103. It will be noted that the pressure in the chamber to the left of piston 68 and above the piston 88 is of a magnitude determined by the amount of the throttling effect of valve 130. This slight pressure is sufficient to maintain pistons 68 and 88 in the parked position shown in FIG. 4.

Reversal valve 100 will occupy the position shown in FIG. 5 when the motor is parked. It is maintained in this position by routing pressurized fluid to opposite ends of the reversal valve 100. Equal pressure acting on opposite sides maintains the valve stable. The fluid is directed to the left side of reversal valve 100, as viewed in FIG. 5, through pressure chamber 150, to the space between land 144 and land 166 of control valve 97, thence through duet 168 and conduit 170, through notch 172 in pilot valve 70 to conduit 178 in cover plate 50, through aperture 178' in porting plate 58, to conduit 178" in motor housing 46 through duct 180. Pressurized fluid is directed to the right side of reversal valve 100 through pressure chamber 150 to conduit 182, through groove 184 of pilot valve 70 thence through conduit 186 in cover plate 50, through aperture 186' in porting plate 58, to conduit 186" in motor housing 46 through duct 188 in motor housing 46. Since the pressure is equal on both sides of the spool valve it will remain in the parked position shown in FIG. 5.

The flow from the pump through the power steering valve 28 or other fluid operated accessory is continuous to thereby provide a continuous supply of hydraulic fluid for wiper motor operation; however, whenever the hydraulic motor is in operation the flow in the hydraulic circuit will pass through control housing 34. Thus motor 14 will not provide any appreciable restriction to flow of hydraulic fluid and, therefore, will not load pump 20.

When it is desired to place the motor 14 in operation, lever 16 is manipulated through the manual control and Bowden cable 18 to move lever 16 from a position shown in FIG. 5 to the position shown in FIG. 6, causing a corresponding movement of control valve assembly 97. This will close duct 168 to pressurized hydraulic fluid and open it to exhaust through the portion of control housing bore 122 to the right of land 166 through the clearance of stem 116 and opening 168. As the control valve 97 moves further to the left as viewed in FIG. 4 port 149 will be closed to the inlet 32 and the tapered portion of land 142 will recede from its seat 167 causing gradually increased opening of the port 169 leading to pressure chamber 150, thereby increasing the rate of flow and thus the speed of the motor. .The duct 190, which is open to exhaust in the parked position, will now be closed to exhaust and opened to the pressurized chamber 150. The hydraulic fluid now entering control valve housing 34 and passing between lands 142 and 144 is routed into pressure chamber 150 and duct 190, through conduit 192, past check valve 194 which is biased toward a closed position by spring 194', and into chamber 120 on the opposite side of pressure regulating piston 118 from spring 138.

The foregoing path is followed by the hydraulic fluid because as control valve 97 was moved to the left from the position shown in FIG. 5 to the position shown in FIG. 6, spring 138 was compressed to therefore provide a greater resistance to valve 130 against opening to permit fluid to bypass. Furthermore, the hydraulic fluid under increased pressure acting on the outer face of the pressure-regulating piston 118 causes it to move from its position shown in FIG. 5 to its position shown in FIG. 6 against the bias of spring 138. This movement was possible because the only force opposing the movement of piston 118 was the bias of spring 138 which was much less than the force of hydraulic fluid on the outer face thereof. The hydraulic pressure on the inner face of the pressure regulating piston 118 is at an exhaust value near zero because this inner face is in communication with conduit 102 leading to the exhaust line 36. In this manner flow of hydraulic fluid through the wiper motor is restricted to thereby build up pressure for motor operation.

After control valve 97 has been moved to the position shown in FIG. 6 the hydraulic fluid under operating pressure will pass from pressure chamber 150 into conduit 182 leading to the pilot valve 70. Pilot valve 70 will be in the position shown in FIGS. 5 and 6 thereby permitting the high-pressure hydraulic fluid in conduit 182 to pass into conduit 186 through the groove 184 in the pilot valve. Conduit 186 is in communication with the chamber to the right of land 196 (FIG. 6) of reversal valve 100 through opening 186' in porting plate 58, conduit 186" and duct 188. Thus the high pressure will move reversal valve 100 to the left. There is only exhaust pressure opposing such movement because the chamber to the left of land 154 is in communication with exhaust line 36 through conduit 102, duct 180, conduit 178", aperture 178' in porting plate 58, conduit 178 in cover plate 50, groove 172 in pilot valve 70, conduit 170 in the cover plate 50, duct 168, control valve housing 34 to the right of control valve 97, opening 128 in control valve 97, bypass valve 97" to duct I48, aperture 148' in porting plate 58 and exhaust chamber 103 in motor housing 46;.

The movement of reversal valve 100 to the position shown in FIG. 6 will cause high-pressure fluid to be routed from pressure chamber 150 through opening 150 in porting plate 58 to duct 150" and to the chamber to the right of motor piston 68 (FIG. 6) through the portion of reversal valve chamber 98 between lands 152 and 196, through duct 156. The movement of the piston 68 in a clockwise direction will be effected because the hydraulic fluid in the chamber to the left ofpiston 68 is in communication with exhaust port 102 through duct 158, the portion of reversal valve chamber 98 between lands 152 and 154, and exhaust chamber 103. The foregoing clockwise movement of piston 68 will continue until reversal is effected by the flat of shaft 60 engaging tooth 72 on pilot valve 70 causing the pilot valve to move from its position shown in FIGS. 5 and 6 to its position shown in FIG. 4.

However prior to the piston 68 leaving its parked position high pressure fluid will be routed to the underside of piston 88 in auxiliary motor chamber 82 from duct 156 through conduit .206, through sequence valve port 204, sequence valve chamber 202, sequence valve port 200", aperture 200, conduit 200 and conduit 198 to the lower side of piston 88 in auxiliary chamber 82. Fluid will be exhausted from the upper side of the piston 88 in chamber 82 through port 164, aperture 162 in porting plate 58, conduit 160 and duct 158 in motor housing 46 through the portion of reversal valve housing 98 between lands 152 and 154, through exhaust chamber 103 to exhaust port 102. This will effect movement of the secondary drive shaft 86 outwardly of the chamber 82 prior to movement of the piston 68 in a clockwise direction from its parked position. The sequence valve is retained in open position by engagement with primary piston 68 when the piston is parked beyond its running range. When the piston 68 leaves the parked position spring 208 will cause sequence valve 210 to close port 204 and the sequence valve 210 will remain closed until piston 68 again returns to the parked position shown in FIG. 5. The trapped fluid between the sequence valve 210 and the piston 88 will retain the drive shaft 86 in its outermost position during running of the motor.

When the piston 68 moves clockwise to the end of its running range the flat portion 75 on the end 74 of primary shaft 60 engages tooth 72 of pilot valve 70 rotating the pilot valve from the position shown in FIGS. 5 and 6 to the position shown in FIG. 4 wherein the groove 184 in pilot valve 70 ef fects communication between conduit 212 in cover plate 50 and conduit 186. The groove 172 effects communication between the conduit 178 and the conduit 182. The shifting of pilot valve 70 redirects the fluid flow causing shifting of the reversal valve and consequent reversing of the primary piston 68. Pressurized hydraulic fluid flows from the inlet port 32 through control valve assembly 97 to pressure chamber 150, thence through conduit 182 and groove 172 of pilot valve 70, to conduit 178, through aperture 178 in porting plate 58, to conduit 178" in motor housing 46, through duct 180 to the left side of reversal valve 100 as seen in FIG. 4. When the reversal valve 100 is moved to the position shown in FIG. 4 at the reversal point of the motor, fluid is exhausted from the right side of the reversal valve 100 through duct 188 and conduit 186", through aperture 186 in porting plate 58. through conduit 186 in cover plate 50, through groove 184 in pilot valve 70, to conduit 212, to duct 148, through aperture 148 in porting plate 58, to exhaust chamber 103 and thence to exhaust port 102. The loop L intersecting conduit 212 at junctions :1 and b is a pressure relief passage to prevent excessive stresses on porting plate 58.

From pressure chamber 150 pressurized hydraulic fluid also flows through aperture 150 in porting plate 58, through duct 150" in motor housing 46, through the reversal valve housing 98 between lands I52 and 154 of reversal valve 100 to duct 158 and thence to the left side of piston 68 to drive piston 68 counterclockwise. When this occurs it will be seen that pressurized fluid is directed through duct 158, conduit I60, aperture 162 in porting plate 58 and port 164 to the upper side of the secondary piston 88 in auxiliary motor chamber 82. However since the pressurized fluid is trapped between sequence valve 210 and the underside of piston 88, piston 88 remains in its uppermost position as seen in FIG. 4. Thus although as the motor operates the upper side of secondary piston 88 will be subjected alternately to exhaust pressure and intake pressure,

the piston 88 will not move until the sequence valve 210 is lifted off its seat by engagement with primary piston 68 during its return to the parked position.

Fluid is exhausted from the rightside of the primary piston 68 through duct 156 and through reversal valve housing 98 between lands 152 and 196 of reversal valve 100 to exhaust.

chamber 103 and thence to exhaust port 102. The piston 68 continues to move counterclockwise until the flat 75 of the primary drive shaft 60 again engages the pilot valve tooth 72 to shift the pilot valve 70 back to the position shown in FIG. 6 which causes shifting of the reversal valve 100 and consequently reversal of primary piston 68. The flow through the motor is then identical to the flow when the motor was initially started as in FIG. 6; however, the pilot valve 70 is shifted by engagement with the flat 75 of the primary drive shaft 60 prior to the engagement of piston 68 with the projecting stern of the sequence valve 210. Thus the secondary piston 88 and the secondary drive shaft 86 are not affected while the motor is operating in its running range. The primary piston 68 continues to oscillate alternately clockwise and counterclockwise until the Bowden cable 18 actuates the lever 16 to the parked position shown in FIG. 5. When the lever 16 is returned to the position shown in FIG. 5, control valve assembly 97 returns to the right, driven by the spring 138, to the position shown in FIG. interrupting flow between the intake port 32 and a duct I90; check valve I94 is urged to a closed position by spring I94 thus interrupting flow of pressurized fluid to the chamber 120, acting on the left side of piston 118. The fluid in the chamber 120 passes through the clearance between the piston I18 and the wall of the control valve chamber 97 to the discharge port 102. The spring 138 thus returns piston 118 to the position shown in FIG. 5, thereby relieving the spring force on the bypass valve 97" permitting continuous flow through the control valve housing from the inlet port 32 to the discharge port 102.

Assuming that when the lever is actuated to parked position the piston 68 is moving clockwise as in FIG. 6, the piston 68 will continue to move clockwise until the pilot valve 70 is shifted to the FIG. 4 position resulting in shifting of the reversal valve 100 as described above. Then the piston 68 will move in a counterclockwise direction until the pilot valve 70 is again shifted, at which time fluid flow through the motor will occur as in the original parked position as described above, thereby driving the piston 68 beyond its running range to the parked position shown in FIG. 5. When this occurs piston 68 engages the stern of the sequence valve 210 causing the sequence valve 210 to open. Then flow will take place through the auxiliary motor chamber 82 as described hereinabove when the motor is in parked position and will cause retraction of the secondary piston 88 and the secondary drive shaft 86.

Another modification of the invention is shown in FIGS. 7 and 8. In order to avoid undue lengthy description, only the differences between the modification of the invention illustrated in FIGS. 1 to 6 and the modification illustrated in FIGS. 7 and 8 will be described in detail; these differences relate only to the porting through the sequence valve to the auxiliary chamber 82. In this modification the conduit 206 leading from the duct 156 to the port 204 is omitted; it is replaced by a conduit 306 which communicates through the porting plate connecting port 204 with duct 190 in control valve housing 34.

The conduit 160 and motor housing 46 and opening 162 in porting plate 58 is omitted; it is replaced by the conduit 310 which effects communication between port 164 on the upper side of piston 88 and auxiliary motor chamber 82 on conduit 170. Thus when the motor is in parked position (FIG. 8) the portion of chamber 82 below secondary piston 88 is exhausted through conduit 198, conduit 200, aperture 200 in porting plate 58, through port 200", sequence valve 210, port 204 to conduit 306, through the porting plate 58 to duct 190; thence through chamber 120 of control valve housing 34 to duct 148 through porting plate 58 to exhaust chamber 103 and port I02. Pressure in the parked position is applied to the upper side of piston 88 from pressure chamber 150 to duct 168, to

conduit 310, through conduit and conduit 310 to port 164.

When the motor is turned on (FIG, 7) and piston 68 leaves its parked position, sequence valve 210 closes to trap pressurized fluid between piston 88 and the sequence valve 210 as in the FIGS. 4, 5 and 6 embodiment; however, during operation in the running range the upper side of piston 88 is continuously exposed to exhaust through conduit 310, conduit 170, duct 168, thence through port 128 in control valve 97' and through bypass valve 97 to exhaust port 102, through duct 148 and exhaust chamber 103.

It should now be apparent that a unique motor has been provided which provides for sequential operation of a primary oscillating piston and a secondary reciprocating pistonthe secondary piston moving its drive shaft to an extended position prior to initial movement of the primary piston and returning to its parked position only subsequent to the movement of the primary piston to its parked position beyond the running range. The invention is illustrated for use with a windshield wiper system wherein the primary piston oscillates to actuate a pair of wipers in an arcuate path across the windshield while the secondary piston operates a drive shaft which in turn operates a cowl panel beneath which the windshield wipers are concealed in parked position, When the motor is turned on, extension of the secondary drive shaft 86 causes the cowl panel 38 to open followed by reciprocation of the primary drive shaft 60 which causes the wipers to operate in their running range on the windshield. When the wiper motor is turned off the wipers driven by primary drive shaft 60 return to their parked position beyond the running range followed by retraction of the drive shaft 86 to cause the cowl panel to close and conceal the wiper arms. Although the invention has been shown and described for operating a concealed windshield wiper system it will of course be apparent that the motor may be used for other and different purposes wherever this type of sequential operation is required. Furthermore, other modifications are possible within the scope of the invention including for example variations in porting to cause the piston to park either right handed or left handed.

Certain specific embodiments of the invention have been described for the purposes of illustration but it will be apparent that various modifications and other embodiments are possible within the scope of the invention. It is to be undcrstood, therefore, that the invention is not limited to the specific arrangement shown but in its broadest aspect it includes all equivalent embodiments and modifications which come within the scope of the invention.

What is claimed is:

1. A fluid pressure motor comprising a housing having a main chamber and an auxiliary chamber, a primary piston having a drive shaft secured thereto reciprocable within said main chamber, a secondary piston having a drive shaft secured thereto reciprocable within said auxiliary chamber, valve means and conduits for alternately routing pressurized hydraulic fluid to one side of said primary piston while exhausting the other side thereof and vice versa and also for alternately routing pressurized fluid to one side of said secondary piston while exhausting the other side thereof and vice versa and means for effecting communication between a source of pressurized fluid and said valve means, and means for interrupting communication to one side of said secondary piston whereby said primary and secondary pistons are reciprocated within said main and auxiliary chambers respec tively when said valve means is in communication with a source of pressurized fluid and whereby said primary piston can reciprocate while said secondary piston remains stationary.

2. A fluid pressure meter according to claim 1 including controller means for starting said motor and for causing said primary piston to move to a parking position at an end of a stroke beyond its running range.

3. A fluid pressure motor according to claim ll including controller means for causing said primary piston to move to a parking position in a region at an end of its stroke beyond its running range, said means for interrupting communication to one side of said secondary piston being responsive to movement of said primary piston in the region of its parking position.

4. A fluid pressure motor comprising a housing having a main chamber and an auxiliary chamber, a primary piston having a drive shaft secured thereto reciprocable within said main chamber, a secondary piston having a drive shaft secured thereto reciprocable within said auxiliary chamber, valve means and conduits for alternately routing pressurized hydraulic fluid to one side of said primary piston while exhausting the other side thereof and vice versa and also for alternately routing pressurized fluid to one side of said secondary piston while exhausting the other side thereof and vice versa and means for effecting communication between a source of pressurized fluid and said valve means, and sequence valve means responsive to movement of the primary piston for controlling fluid flow through said auxiliary chamber to effect sequential movement of said secondary piston relative to said primary piston.

5. A fluid pressure motor according to claim 4, wherein said sequence valve means comprises a valve having a part thereof disposed in said main chamber and engageable with said primary piston for actuation thereby.

6. A fluid pressure motor according to claim wherein said sequence valve means includes biasing means for normally retaining said valve in closed position.

7. A fluid pressure motor according to claim 6 wherein said valve means is actuated to open position when engaging said primary piston.

8. A fluid pressuremotor according to claim 7 wherein said sequence valve means is disposed in circuit with said auxiliary chamber communicating with one side of said secondary piston whereby it is effective to interrupt fluid flow to one side of said secondary piston when closed.

9. A fluid pressure motor according to claim 8 wherein said primary piston engages said valve to cause said valve to open only when said primary piston is disposed in the parking region.

10. A fluid pressure motor comprising a housing having a main chamber and an auxiliary chamber, a primary piston having'a drive shaft secured thereto reciprocable within said rnain chamber, a secondary piston having a drive shaft secured thereto reciprocable within said auxiliary chamber, valve means and conduits for alternately routing pressurized hydraulic fluid to one side of said primary piston while exhausting the other side thereof and vice versa and also for altemately routing pressurized fluid to one side of said secondary piston while exhausting the other side thereof and vice versa and means for effecting communication between a source of pressurized fluid and said valve means, and a sequence valve assembly comprising a sequence valve, spring biased to closed position, for interrupting fluid flow to one side of said secondary piston when said sequence valve is closed to thereby cause movement of said secondary piston only when said sequence valve is open, normally operable control means for starting said motor and for parking said motor in a position at an end of its stroke beyond its running range, said sequence valve having a portion extending into said main chamber operatively engageable with said primary piston when said piston is in said parked position beyond its running range for actuation to open position, whereby said secondary piston moves in one direction prior to said primary piston leaving its parked position and in an opposite direction following the return of said primary piston to its parked position.

UNITED STATES PATENT orwcr @EHMQATE W (IQEMWN Patent 3.645 ,l68 Dated Februarv 29, 1972 Inventor(s) Anthony R. D'Alba It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Abstract, line 2 change "oscillated" to --oscillates-.. Col. 10, line 29 change "said piston" to -said primary piston-m.

Signed and sealed this 17th day of October 19720 Attest:

EDWARD MQFLETCHEMJRQ, ROBERT GOTTSGHALK Attesting Officer Coissioner' of Patents :ORM POWSO uoeg) USCOMM-DC 6O376-P69 [L5, GOVERNMENT PRINTING OFFICE: I969 0-366334 

1. A fluid pressure motor comprising a housing having a main chamber and an auxiliary chamber, a primary piston having a drive shaft secured thereto reciprocable within said main chamber, a secondary piston having a drive shaft secured thereto reciprocable within said auxiliary chamber, valve means and conduits for alternately routing pressurized hydraulic fluid to one side of said primary piston while exhausting the other side thereof and vice versa and also for alternately routing pressurized fluid to one side of said secondary piston while exhausting the other side thereof and vice versa and means for effecting communication between a source of pressurized fluid and said valve means, and means for interrupting communication to one side of said secondary piston whereby said primary and secondary pistons are reciprocated within said main and auxiliary chambers respectively when said valve means is in communication with a source of pressurized fluid and whereby said primary piston can reciprocate while said secondary piston remains stationary.
 2. A fluid pressure motor according to claim 1 including controller means for starting said motor and for causing said primary piston to move to a parking position at an end of a stroke beyond its running range.
 3. A fluid pressure motor according to claim 1 including controller means for causing said primary piston to move to a parking position in a region at an end of its stroke beyond its running range, said means for interrupting communication to one side of said secondary piston being responsive to movement of said primary piston in the region of its parking position.
 4. A fluid pressure motor comprising a housing having a main chamber and an auxiliary chamber, a primary piston having a drive shaft secured thereto reciprocable within said main chamber, a secondary piston having a drive shaft secured thereto reciprocable within said auxiliary chamber, valve means and conduits for alternately routing pressurized hydraulic fluid to one side of said primary piston while exhausting the other side thereof and vice versa and also for alternately routing pressurized fluid to one side of said secondary piston while exhausting the other side thereof and vice versa and means for effecting communication between a source of pressurized fluid and said valve means, and sequence valve means responsive to movement of the primary piston for controlling fluid flow through said auxiliary chamber to effect sequential movement of said secondary piston relative to said primary piston.
 5. A fluid pressure motor according to claim 4, wherein said sequence valve means comprises a valve having a part thereof disposed in said main chamber and engageable with said primary piston for actuation thereby.
 6. A fluid pressure motor according to claim 5 wherein said sequence valve means includes biasing means for normally retaining said valve in closed position.
 7. A fluid pressure motor according to claim 6 wherein said valve means is actuated to open position when engaging said primary piston.
 8. A fluid pressure motor according to claim 7 wherein said sequence valve means is disposed in circuit with said auxiliary chamber communicating with one side of said secondary piston whereby it is effective to interrupt fluid flow to one side of said secondary piston when closed.
 9. A fluid pressure motor according to claim 8 wherein said primary piston engages said valve to cause said valve to open only when said primary piston is disposed in the parking region.
 10. A fluid pressure motor comprising a housing having a main chamber and an auxiliary chamber, a primary piston having a drive shaft secured thereto reciprocable within said main chamber, a secondary piston having a drive shaft secured thereto reciprocable within said auxiliary chamber, valve means and conduits for alternately routing pressurized hydraulic fluid to one side of said primary piston while exhausting the other side thereof and vice versa and also for alternately routing pressurized fluid to one side of said secondary piston while exhausting the other side thereof and vice versa and means for effecting communication between a source of pressurized fluid and said valve means, and a sequence valve assembly comprising a sequence valve, spring biased to closed position, for interrupting fluid flow to one side of said secondary piston when said sequence valve is closed to thereby cause movement of said secondary piston only when said sequence valve is open, normally operable control means for starting said motor and for parking said motor in a position at an end of its stroke beyond its running range, said sequence valve having a portion extending into said main chamber operatively engageable with said primary piston when said piston is in said parked position beyond its running range for actuation to open position, whereby said secondary piston moves in one direction prior to said primary piston leaving its parked position and in an opposite direction following the return of said primary piston to its parked position. 